Umbrella



FIG. 1 is a perspective view of the umbrella showing the new design of this invention;

FIG. 2 is a front elevational view thereof; the rear elevational view, the left side elevational view and the right side elevational view being a mirror image thereof;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a bottom plan view thereof. 

The ornamental design for an umbrella, as shown. 